Field of the Invention
The present invention relates to a temperature compensation method for a gas sensor module using a change of heater current, and particularly, to a compensation method for compensating an output voltage by measuring a resistance or current of a heater disposed in a gas sensor module.
Description of Related Art
Carbon dioxide as a gas is chemically very stable in the atmosphere and is a primary cause of global warming. The need for controlling the concentration of carbon dioxide has increased for indoor air-conditioning of a building and horticulture in addition to an environmental issue, and as a result, research into a method for measuring the concentration of carbon dioxide gas which exists in the atmosphere has been actively conducted.
As the method for measuring the concentration of the carbon dioxide gas which exists in the atmosphere at present, an optical method (NDIR scheme) is provided and the present scheme is a scheme that measures the concentration of carbon dioxide by measuring an absorption degree of infrared rays using a principle in which the carbon dioxide absorbs only infrared rays having a specific wavelength. Further, a solid electrolyte or semiconductor type gas sensor also exists and a detecting principle of the semiconductor type gas sensor adopts a phenomenon (a change in electric conductivity, that is, resistance or thermal conductivity) induced as target gas is adsorbed on or desorbed on the surface of a ceramic (oxide) semiconductor.
In the present regard, Korean Patent Unexamined Publication No. 10-2009-0083125 (TEMPERATURE-COMPENSATED GAS MEASUREMENT APPARATUS FOR NANO DEVICE GAS SENSOR) in the related art discloses a gas measurement apparatus using a nano-device gas sensor, which can accurately compensate a resistance value in the gas measurement apparatus which is changed depending on a temperature, and verify a temperature compensation degree and whether a circuit malfunctions.
However, in the related art, there is a problem in that since analog circuits including a Wheatstone bridge, etc., are required in the gas sensor and the temperature is directly compensated by measuring the change in temperature in the gas sensor, a high-priced temperature sensor is particularly required.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.